The Chicago Metallic Commercial II Nonstick Mini Loaf Pans, Set of 4 is made from commercial heavy weight aluminized steel. Even heat distribution allows for even cooking and browning. All Chicago Metallic Commercial II Bakeware is made for durability - the pans won't rust or corrode and metal utensils can be used on their uncoated surfaces. The reinforced lip (on all folded and rectangular pans) eliminates popping, bending and flexing. The folded construction (on rectangular, loaf and square pans) is triple thick in the corners to increase strength and resist warping. Chicago Metallic Commercial II Bakeware is the choice of commercial bakers. The more you use it the better it gets. Dishwasher safe. Lifetime warranty. Set of 4.